RC Airplane World Forum

Thanks TeamCF and KILOP...

I never really considered that a 4 channel plane may "need" ailerons to turn, or that a 3 Channel plane isn't just a plane lacking ailerons. You both have some great points to keep in mind. That is the beauty of these forums. (and why I am a beginner)

The more I learn about this hobby, the more I learn there is more to learn. But that keeps it new and fun, I suppose.

The Catalina I am looking at is described as "able to perform some aerobatics" and "very stable." I will take these descriptions with a grain of salt and have to see how she performs in the air. And yes, very light on the controls. Less is more. The first flight may have a very steep learning curve.

Matt

Matt and all,

It is not posssible to teach one " how to fly a model airplane" by writing although we often see such instructions in manual accompanying kits or ARF and RTF.

I will simply mention the following _ _ _
The main problem that self educating new pilot run into is due to "over-controlling".

One only explanation _ _ _ (as an example) _ _ _
The pilot see his model climbing . . .
He should reduce the power setting . . .
Instead he gives down elevator and too much . . .
The plane rotates in pitch and noses down . . .
He gives up elevator and again TOO MUCH . . .
The plane goes into a climb worst than before . . .
Here a second time comes down elevator . . .
Again TOO MUCH . . .

Be gentle on the control. Give time for the airplane to respond. The airplane has mass and every change is an acceleration or a deceleration.

One very important thing (often not even brought up by an instructor) is that this mass has inertia.

Another example is going into a turn. Not only the plane has to accelerate from a wing level attitude but this acceleration has to be decelerated.

If you use the ailerons or the rudder to initiate the turn and put the model in a banked attitude that new attitude has to be controlled and the roll has to be stopped for the banked attitude to be as desired.

In different words, the use of ailerons to bank the airplane has to be stopped by opposite ailerons.
When initiating a turn with rudder only the model will bank due to the model slipping outward of the turn. Again that rolling motion has to be stopped at the degree of bank desired. The change of direction of the flight needs a force provided by the wings, so some more lift is needed thus some small amount of up elevator to increase the angle of attact.

Do not over-control and your progress as a pilot will be much, MUCH faster.

The same occur with new trainee learning to fly full size airplanes.

Here is where a good instructor plays a valuable role.

KILOP

I knew someone (years ago in my old club) who did just that - he had a 4 channel trainer but for some reason wanted to learn on 3 channels ( ) and so he disconnected the aileron servo and taped the ailerons up so they wouldn't move in flight; the plane flew fine, no different to a standard 3 ch trainer!
It wasn't long before he untaped and connected up the ailerons, and he didn't have any trouble making the transition from 3 to 4 channels, from what I can remember.

As additional information _ _ _

The main differences that MAY exist between a 3 channel and a 4 channel model are _ _ _

(notice I wite "that MAY exist" . . . I did not write "that DO exist")

-- The 3 channel may have more dihedral and may also have some more sweepback. Both help the lateral stability and help the model to return by itself toward straight flight. Straight flight meaning wings level but not necessarily maintaining altitude.

Notice again that I am not writing "straight and level". Level flight, maintaining altitude, is achieved by proper balance around the lateral axis (wing tip to wing tip). That balance to fly level is the result of power setting, CG location, thrust line angle (up or down thrust) and whether the CG is below or above the lift force.

We must not confuse lateral stability with longitudinal stability.

If a model is designed for 4 channels including the ailerons, such a model may have less dihedral, no sweepback and less lateral stability.

Making the ailerons inactive can result in a model more difficult to fly than one originally designed for only 3 channels since such a 4 channel design may have much less lateral stability.

If one wishes to simplify flying by using only 3 controls, I personally feel that using ailerons instead of rudder makes the control easier.

Keep in mind that to turn, a force toward the inside of the curve (centripetal force) is provided by the lift of the wings. The wings have to be banked and has to be increased to provide both "a force to counteract the weight" and "a force to work against the centrifugal force".

With rudder only, the banking is achieved by the model slipping outward of the turn and the dihedral and/or swepback or both creates more lift from the outward wing thus rolling the model. The amount of banked achieved is more difficult to control than with ailerons.

It is easier to control a 3 channel with ailerons as compared to with rudder because we have a direct control of the banking attirude.

Do not hesitate to ask questions. You will get answers.

Happy flying,

KILOP
.

Concerning my previous posting . . .

It appears to me that there is a limit to the length of a posting in this forum.

I wanted to provide additonal information but could not add more lines for reasons I do not know.

So, again, do not hesitate to ask questions if more info is desired.

KILOP

For me the change is actually quite difficult. I am used to four channels, using a mode 2 transmitter. Since the rudder control is on the left stick on four channels it becomes second nature to adjust a little on take off and landing. When I decided to make my Monocoupe a three channel I wanted to control both elevators and rudder with the right stick. I'm sure once it is in the air I will be fine, but when I taxi I am always trying to turn it with the left stick instead of the right one. Confusing!

Jeff,

That is not a problem.

Just switch them.

KILOP

I must admit, I have that exact concern. I don't really want to learn one way, then have to unlearn it when learning another. However,...I was thinking it might be nice to be able to "simplify" the plane in order to let some friends give it a try.

You can fly the model either way _ _ _

If you want to fly 3 channels just disconnect either the rudder or the ailerons and tape the disconnected one. Disconnect does not mean the linkage, it means just unplug the connection on the receiver.

If you use the rudder you can put it on either the left stick as it is in mode 2 or simply switch it over to the right stick (as I implied in my previous posting).

Same if you use the ailerons. You can leave them on the right stick or switch them to the left stick.

Note that many 3 channel transmitters have elevators on the left and rudder on the right.

Just set it the way you wish and remember any switching when setting up travels, linearity or exponential.

Same if you need a servo reversal.

KILOP

Personally I wouldn't want to learn one way then another either, I was just sharing a fellow flyer's experience in doing exactly that

From Paul:


I know this is going very off topic, but let me know what's happening Paul and I'll look into it. As fas as I know there isn't any restriction on character limits etc.